Configurable Product not working after successful upgrade to 2.1.2

[TGWS2016]

Preconditions

1. Magento 2.1.2

Steps to reproduce

1. Upgraded from 2.1 to 2.1.2 - no issues reported.
2. Went to create a new "Configurable Product"
3. Added the configurations, entered in the images/appropriate values into the configurations
4. Pressed save, and the configurations are gone.
5. This also happens on a currently saved configurable product, when you go in to view only, then if you click on Save, it removes all configuration products from the configuration. (these were there before).

Expected result

1. Configurations should be saved.

Actual result

1. Configurations within the Configurable product missing.

Best,
Craig